1. Field of the Invention
The present invention relates to an optical device.
2. Description of the Related Art
US Patent Application Publication US 2007/0195538 A1 discloses an optical device formed by joining an optical fiber holding member (a ferrule and a flange) to hold an optical fiber and a light conversion member holding member (cap) to hold a light conversion member. In this optical device, a joint of the optical fiber holding member and the light conversion member holding member is performed by YAG-welding the end faces of the flange and cap to each other, which face each other parallel on a plane perpendicular to the optical axis of the optical fiber.
In the optical device according to the prior art, both the joint surfaces of the optical fiber holding member and light conversion member holding member are parallel to a plane perpendicular to the optical axis of the optical fiber. For this reason, reducing the diameter of the optical device will greatly reduce the joint strength because of a reduction in joint area. This may fail to secure a joint strength required for the device. This is the problem that arises regardless of the joining method to be used. Joining with a general adhesive, in particular, is inferior in joint strength to joining by welding, and thus this problem is more noticeable.